Remove specific prevalent malware with Windows Malicious Software Removal Tool
Tools are beginning to emerge that can be used to begin the process of recovering files encrypted by WannaCry on some Windows systems.
Source: Malware Available Tools Making Dent in WannaCry Encryption
Further to the above Microsoft released the following:
Today (22nd May 2017), we released an update to the Microsoft Malicious Software Removal Tool (MSRT) to detect and remove WannaCrypt malware. For customers that run Windows Update, the tool will detect and remove WannaCrypt and other prevalent malware infections. Customers can also manually download and run the tool by following the guidance here. The MSRT tool runs on all supported Windows machines where automatic updates are enabled, including those that aren’t running other Microsoft security products.
The MSRT can be downloaded here: https://support.microsoft.com/en-us/help/890830/remove-specific-prevalent-malware-with-windows-malicious-software-removal-tool